This invention relates to a grommet which prevents an elongated member such as a wire harness, passing through an opening portion formed in a mounting member, from contacting with the opening portion, and also prevents the intrusion of water through a gap between the opening portion and the elongated member.
The invention also relates to a grommet which is mounted on a waterproof box containing a control unit or the like, and is used to cause a wire harness to be extended outwardly from the waterproof box.
The invention further relates to a grommet and a grommet-mounting structure.
For example, when an elongated member, such as a wire harness, is to be passed through an opening portion formed in a mounting member such as a car body panel of an automobile and an electric connection box, a grommet is used in order to prevent the wire harness from contacting the opening portion and also to prevent the intrusion of water through a gap.
In recent years, usually, the whole of a grommet of this kind has been molded into an integral construction, using a soft (flexible) elastic material such as synthetic rubber.
However, when a wire harness or the like is to be passed through such a grommet entirely molded into an integral construction by the use of a soft elastic material, the diameter of the grommet must be expanded, and this operation requires much time and labor, and therefore was cumbersome.
Therefore, in order to deal with this problem, there has been proposed a grommet enabling a wire harness or the like to be easily passed therethrough (see, for example, pages 3 and 4 and FIGS. 1 to 4 of JP-A-8-31251). In this grommet, a grommet body is made of a rigid material such as a rigid plastics material, and is divided to have a two-piece construction. Soft elastic members for waterproof sealing purposes are provided respectively at parting surfaces of division members and contact surfaces of the division members for contact with an opening portion.
A grommet 1, shown in FIG. 22, includes a pair of division members 1a and 1b separated from each other in a plane in which a longitudinal axis of the grommet lies. Each of the division members 1a and 1b is molded into an integral construction, and includes a half-cylindrical division member 2a, 2b, a half-annular division member 6a, 6b, and an elastic division member 12a, 12b. 
The half-cylindrical division members 2a and 2b are mated together at their parting surfaces to form a generally cylindrical body, and include a lock mechanism having retaining claws 3 and retaining hole portions 4 formed integrally therewith. The half-cylindrical division members 2a and 2b are injection molded of a rigid plastics material such for example as polypropylene.
The half-annular division members 6a and 6b are mated together at their parting surfaces to form an annular body, and a guide projection 8 and a guide hole 9 are formed at the parting surface of each of these division members. The half-annular division members 6a and 6b are injection molded of a rigid plastics material as described for the half-cylindrical division members.
The elastic division member 12a interconnects the half-annular division member 6a and the half-cylindrical division member 2a, while the elastic division member 12b interconnects the half-annular division member 6b and the half-cylindrical division member 2b. Each of the elastic division members 12a and 12b is made of a soft elastic material such as rubber and a plastics elastomer.
Half-annular grooves 15a and 15b for fitting a peripheral edge portion of the opening portion formed in a car body panel are formed in outer peripheral surfaces of the elastic division members 12a and 12b, respectively. Ridge-like seal portions 18a, 18b extending along the parting surface of the half-cylindrical division member 2a, 2b, and a seal tongue 19a, 19b are formed integrally on each of the elastic division members 12a and 12b. 
As the soft elastic material, there can be used an olefin elastomer or a plastics elastomer (such as a styrene elastomer) which has good compatibility with the plastics material (such as polypropylene) of which the half-cylindrical division members 2a and 2b and the half-annular division members 6a and 6b are made. There is used a so-called double injection-molding method in which the half-cylindrical division member 2a, 2b and the half-annular division member 6a, 6b are put in a cavity of a mold which corresponds in shape to a half of the grommet, and a molten elastic material is poured into this cavity.
The grommet 1 of the above construction in a divided condition grips the wire harness (not shown), and then the division members 1a and 1b are mated together, and are fastened together into an integral condition into by the lock mechanism. At this time, the ridge-like seal portions 18a and 18b, provided at the parting surfaces of the half-cylindrical division members 2a and 2b, abut against each other to be squeezed, and therefore there is no fear that a gap is formed between the mated parting surfaces.
Further, the grommet, thus assembled into the integral condition, is passed through the opening portion (not shown) in the car body panel, with the half-cylindrical division members 2a and 2b first fitted thereinto, and the peripheral edge portion of this opening portion is fitted into the half-annular grooves 15a and 15b formed respectively in the elastic division members 12a and 12b. 
As a result, the elastic division members 12a and 12b, each made of the soft elastic material, are held in intimate contact with the opening portion in the car body panel, thereby preventing the intrusion of water through a gap between the grommet 1 and the opening portion.
Incidentally, wire harnesses are installed all over a car body, and therefore it is difficult to remove the wire harnesses from the car body when discarding them. Therefore, in many cases, these wire harnesses are crushed together with the car body and others, and are broken into pieces by a shredder. In recent years, however, it has been required to reduce the amount of shredder dust from the viewpoint of an ecological problem, and also it has been required to recover scrap iron, non-ferrous metals, resins and others in an assorted manner so that the resources can be easily efficiently used.
However, usually, the wire harness includes wires, terminals, connectors, grommets and an insulating tape, and when these parts are crushed together with the car body, and are broken into pieces by a shredder, the different materials are mixed together, so that it is difficult to recover these materials in an assorted manner.
Therefore, before the above crushing step, the wire harness is removed from the car body, and also the parts (including the wires, the terminals, the connectors and the grommets) made of different materials, are removed from the wire harness as much as possible.
However, in the case of the grommet 1 shown in FIG. 22, the half-cylindrical division member 2a, 2b and half-annular division member 6a and 6b which are made of the plastics material are insert molded (double injection molding) in the elastic division member 12a, 12b made of the elastomer having good compatibility with the plastics material, and therefore these bodies are firmly bonded together.
Therefore, when the elastic division member 12a, 12b is to be separated from the half-cylindrical division member 2a, 2b and the half-annular division member 6a, 6b for recovering purposes so as to effect the above recycling process, the bonded portions could not be easily separated from each other, which invited a problem that the efficiency of this operation is low.
One related grommet, used in a waterproof box containing a control unit or the like, is disclosed, for example, in JP-UM-A-3-126315. In this grommet 180, a second thickened peripheral wall portion 183 is formed at a central portion of bellows-like trunk portion 182 of a grommet body 181, and a fitting groove 184 and a guide projection 185 (which serve as fitting portions for rigid plates) are formed at an outer surface of the second thickened peripheral wall portion 185, as shown in FIGS. 23A and 23B.
A first thickened peripheral wall portion 187, formed at a front end of the grommet body, is similar in shape to the second thickened peripheral wall portion, and is one size larger than it. A fitting groove 188 (serving as a fitting portion for a rigid member) is formed in an inner peripheral surface of the first thickened peripheral wall portion 187. An upper end lip 189 is formed on an outer surface of the first thickened peripheral wall portion 187.
In this grommet 180, the rigid member is fitted in the inner peripheral surface of the first thickened peripheral wall portion 187 formed at the front end of the grommet body 181, and retaining claws of this rigid member are retainingly engaged respectively in frame-like retaining portions of a lower case, and a slide projection 190 and a slide peripheral groove 191 of the first thickened peripheral wall portion 187 are fitted relative to a guide groove and a guide projection of the lower case, respectively.
An upper case, having a packing for the upper end lip 189, is provided on the upper side of the first thickened peripheral wall portion 187 to cover the same.
The fitting groove 183 and guide projection 185 of the second thickened peripheral wall portion 183, formed at the central portion of the grommet body, are fitted in a fitting groove, and retaining claws of the lower rigid plate are engaged respectively in frame-like retaining portions of a wall plate such as a heat-insulating plate. An upper wall is fitted relative to the upper rigid plate to be fixed thereto.
In this grommet, however, when the grommet body is to be fitted relative to the lower case, a large inserting force is required for fitting the relevant resin-molded portions together, and therefore there was encountered a problem that the efficiency of the operation was low.
Incidentally, there is already known a relief apparatus for transmitting a relief signal from a submerged vehicle. As shown in FIGS. 24 and 25, such a relief apparatus comprises a detection device 201 for detecting the intrusion of water into the interior of the vehicle, a transmitting device 202 for transmitting a relief signal in response to the detection signal from the detection device 201, and a wire harness 203 connecting the detection device 201 and the transmitting device 202 together.
The transmitting device 202 is received within a waterproof box 205 provided, for example, below a seat 204 of the vehicle. The waterproof box 205 includes a box body 205a having a notch portion 206, and a lid 205b, and the wire harness 203 is extended into the interior of the waterproof box 205 through the notch portion 206, and is connected to the transmitting device 202.
As shown in FIG. 26, a water-stop agent 203b is filled in a predetermined portion of a bundle of (many) wires 203a forming the wire harness 203, and thereafter an adhesive tape 203c is wound on the bundle of wires 203a to cover the same, and that portion of the wire bundle in which the water-stop agent 203b is filled serves as a water-stop portion. A grommet 207, mounted on this water-stop portion, is located at the notch portion 206.
The grommet 207 includes a division member body 207a and a seal portion 207b which are separated from each other along a plane parallel to an axis of a tubular grip portion 208 for gripping the water-stop portion in a circumferential direction, and the division member body 207a and the seal portion 207b are releasably combined together (see, for example, JP-A-8-251769).
The water-stop portion of the wire harness 203 is gripped by the grip portion 208 of the grommet 207 in the circumferential direction, and in this condition the seal portion 207b of the grommet 207 is fitted into the notch portion 206 formed in the box body 205a of the waterproof box 205, and the lid 205b is locked to the box body 205a. Thus, the grommet 207 is located at the notch portion 206 of the waterproof box 205.
When the grommet 207 is located at the notch portion 206 of the waterproof box 205, a seal between the grommet 207 and the notch portion 206, a seal between the grommet 207 and the wire harness 203, and a seal at the water-stop portion are formed. With respect to the waterproof seal between the grommet 207 and the wire harness 203, a waterproof member is interposed between the division member body 207a and seal portion 207b of the grommet 207, and the division member body 207a and the seal portion 207b are fastened together by retaining piece portions and retaining portions provided at opposed portions thereof, thereby securing the waterproof effect.
When the waterproof member is interposed between the division member body 207a and the seal portion 207b, there is a fear that the division member body 207a and the seal portion 207b are fastened together, with the waterproof member twisted or disposed out of position.
In such a case, the operator cancels the retaining engagement between each retaining piece portion and the corresponding retaining portion (which are retainingly engaged with each other at a position concealed from the operator's view), and then puts the waterproof member into the predetermined position and posture by the hand or others so as to secure the desired waterproof effect. Therefore, there is encountered a problem that the efficiency of the operation is low.